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81.
82.
Pedro A. Ochoa George Alexis Sagastume Gutiérrez Juan B. Cogollos Martínez Carlo Vandecasteele 《Journal of Cleaner Production》2010,18(12):1171-1176
An approach to Cleaner Production in a small factory of hydrated lime is presented. The work aims to improving fuel and limestone utilization and reducing waste production in the plant. Efforts mainly focus on the calcination stage, where around 50% of the production costs due to fuel consumption occur. To fulfill this objective, new indicators are proposed to evaluate the performance of the lime shaft kiln, in order to develop an operational control method for the calcination process. The systematic use of the developed operational control method is a powerful tool in the daily operation of a small lime factory, since it allows a more efficient calcination process with reduced environmental impact and production cost. 相似文献
83.
A positive surge results from a sudden change in flow that increases the depth. It is the unsteady flow analogy of the stationary
hydraulic jump and a geophysical application is the tidal bore. Positive surges are commonly studied using the method of characteristics
and the Saint-Venant equations. The article presents the results from new experimental investigations conducted in a large
rectangular channel. Detailed unsteady velocity measurements were performed with a high temporal resolution using acoustic
Doppler velocimetry and non-intrusive free-surface measurement devices. Several experiments were conducted with the same initial
discharge (Q = 0.060 m3/s) and six different gate openings after closure resulting in both non-breaking undular and breaking bores. The analysis
of undular surges revealed wave amplitude attenuation with increasing distance of surge propagation were in agreement with
Ippen and Kulin theory. Also, undular wave period and wave length data were relatively close to the values predicted by the
wave dispersion theory for gravity waves in intermediate water depths. 相似文献
84.
Manzo Sonia Parrella Luisa Schiavo Simona Spaziani Fabio Chiavarini Salvatore Tebano Carlo De Maio Lucio Capone Stefano Siciliano Anna Valeria Armiento Giovanna 《Environmental science and pollution research international》2022,29(55):83291-83303
Environmental Science and Pollution Research - In this study we propose, a multi-step strategy of selection and characterization of long-term dataset of contaminant concentrations in different... 相似文献
85.
For many plant species, seed dispersal is one of the most important spatial demographic processes. We used a diffusion approximation and a spatially explicit simulation model to explore the mechanisms generating seed dispersal kernels for plants dispersed by frugivores. The simulation model combined simple movement and foraging rules with seed gut passage time, plant distribution, and fruit production. A simulation experiment using plant spatial aggregation and frugivore density as factors showed that seed dispersal scale was largely determined by the degree of plant aggregation, whereas kernel shape was mostly dominated by frugivore density. Kernel shapes ranged from fat tailed to thin tailed, but most shapes were between an exponential and that of the solution of a diffusion equation. The proportion of dispersal kernels with fat tails was highest for landscapes with clumped plant distributions and increased with increasing number of dispersers. The diffusion model provides a basis for models including more behavioral details but can also be used to approximate dispersal kernels once a diffusion rate is estimated from animal movement data. Our results suggest that important characteristics of dispersal kernels will depend on the spatial pattern of plant distribution and on disperser density when frugivores mediate seed dispersal. 相似文献
86.
87.
Cesare Dari-Salisburgo Piero Di Carlo Franco Giammaria Yoshizumi Kajii Alfonso D'Altorio 《Atmospheric environment (Oxford, England : 1994)》2009,43(4):970-977
A laser induced fluorescence (LIF) instrument has been developed to measure tropospheric NO2 with low detection limit. The instrument design, development and first measurements are reported. There are also details of the temporal gate system built for the fluorescence acquisition. The instrument is able to make fast measurements (up to 4 Hz) and shows a limit of detection of 10 pptv/60 s. Continuous observations (2 weeks in summer 2007) in a small town in central Italy were used to test the performance of the instrument and to study the photochemistry of ozone in a background site. LIF and a commercial chemiluminescence (CL) instrument simultaneous observations of NO2 show a good linearity (LIF = 1.02 CL + 0.6 (ppb), R2 = 0.98) but there is a bias of the commercial instrument of about 0.60 ppbv on average. The overestimation of the CL system is probably due to conversion of NOy species into NO by the molybdenum converter used in the CL instrument to detect NO2. Analysis of 1 s data is used to test the instrument response and the coupling between nitrogen oxides and ozone. 相似文献
88.
Gloria Antonini Paolo Audisio Emiliano Mancini Alessio De Biase Carlo Tronci Giulia Rossetti Marco Trizzino 《Marine Biology》2010,157(2):371-381
Marine rock-pools, commonly found along the Mediterranean coasts, are isolated patches of habitat characterised by large spatial
and temporal variations. The phylogeography of Calobius quadricollis and C. urbanelliae, two sibling species of moss beetles (Coleoptera, Hydraenidae) inhabiting Italian temporary marine rock-pool ecosystems,
were studied using mitochondrial cytochrome c oxidase subunit I (COI). Our data suggest a strong association between the scored
genetic variability and the geographical distribution of populations sampled for both species. These analyses provided evidences
of episodic species range expansion and fragmentation, recurrent “flush and crash” and bottleneck episodes probably occurring
during the Glacial Cycles. The observed phylogeographical pattern is probably related to the historical and biogeographical
processes of Mediterranean areas, as well as both to the ephemeral habitat tipology and limited dispersal ability of these
beetles. 相似文献
89.
Michael S. Tomlinson Eric H. De Carlo 《Journal of the American Water Resources Association》2003,39(1):113-123
ABSTRACT: Streams in the Hawaiian Islands differ from many streams on the U.S. mainland presenting unique challenges to investigators attempting to characterize Hawaiian streams. Hawaiian streams are short; watersheds are small and steep; and rain events are usually short in duration but intense. As a result, most streams in Hawai'i are flashy. Time scales for storm hydrographs in Hawai'i are on the order of hours instead of days and flash flooding is a common hazard. To characterize the streams we were investigating, we found it necessary to obtain streamflow and water quality measurements at relatively short time intervals. While this resolution resulted in large sometimes onerous quantities of data, we would have otherwise missed certain phenomena, such as 60‐fold flow changes in 15 minutes or 30‐fold turbidity changes in five minutes. Even at five‐minute intervals, we found that attempts to predict TSS using a relationship obtained from in situ turbidity were not always satisfactory. Depending on the precision required, either higher resolution measurements or in vitro turbidity measurements of the TSS samples might be necessary. Finally, these high resolution measurements enabled us to observe other cyclical events that might have been missed if the measurement intervals were greater than one hour. 相似文献
90.
Cristina Zago Gabriele Capodaglio Carlo Barbante Michele Giani Ivo Moret Giuseppe Scarponi Paolo Cescon 《Chemistry and Ecology》2002,18(1):39-51
In the present study the concentrations of cobalt, copper, iron, manganese, zinc were analysed and the speciation of copper and zinc performed, with a summer and winter sampling, for two areas in the Northern Adriatic Sea and crossing at the farthest zones of the Po river-sea water interface. Results show that when salinity increases the concentrations of all investigated metals (with the exception of cobalt) present some degree of biogeochemical cycling. Copper is the element whose dissolved phase has the highest importance in metal transport across the salinity gradient. Results of speciation analysis demonstrate that the presence of excess amounts (5-8 fold) of unbound ligands confers a buffering capacity for potential inputs of dissolved metals into the Northern Adriatic Sea. The speciation of both copper and zinc in the dissolved phase was dominated by organic complexation. 相似文献